Methylmercury and long chain polyunsaturated fatty acids are associated with immune dysregulation in young adults from the Seychelles child development study

Overview

This study examined associations between methylmercury (MeHg) exposure and immune function in 497 young adults (approximately age 19) from the Seychelles Child Development Study, a longitudinal cohort in the Republic of Seychelles characterized by very high habitual fish consumption (approximately 7 fish meals per week). Hair methylmercury was used as the primary biomarker of chronic MeHg exposure. The mean Y19 hair mercury was 10.23 ppm (SD 6.02), substantially above US and European reference population levels. The study found that MeHg and long-chain polyunsaturated fatty acids (LC-PUFAs) were jointly associated with markers of immune dysregulation, with opposing effects that partially modulate one another. This study contributes to the evidence base for fish consumption as a high-exposure pathway for MeHg and the co-exposure trade-off framework between MeHg and beneficial fish nutrients.

Key numbers

n=497 young adults at Year 19 follow-up visit. Mean hair total mercury (Y19Hg): 10.23 ppm (SD 6.02). Fish consumption: approximately 7 meals per week (island population). Method: hair mercury as biomarker of MeHg exposure. Outcome: immune dysregulation markers including cytokines and lymphocyte populations. Jurisdiction: Seychelles (SC). Publication: Environ Res 2020 April;183:109072; PMC 2021 April.

Methods (brief)

Longitudinal cohort study (Seychelles Child Development Study). Hair mercury measured at Year 19 follow-up. ICP-MS or CV-AAS for hair Hg measurement (standard for SCDS). Association analyses adjusting for confounders including LC-PUFA status. Limitation: high-fish-consuming island population; findings may not generalize directly to typical US/EU dietary patterns.

Implications

Certification: Supports MeHg-fish co-exposure framework for seafood categories; documents achievable exposure levels under very high fish consumption. Courses: Key illustration of MeHg exposure through fish consumption and the nutrient-contaminant trade-off in seafood dietary advice. App: High fish consumption frequency is a key modifying factor for MeHg exposure estimates; 7 meals/week population shows hair Hg mean 10 ppm. Microbiome: MeHg immunotoxicity pathways may intersect with gut immune regulation; see mercury-gut-axis.

Wiki pages updated on ingest

• Mercury
• Fish
• methylmercury-immune

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